Vehicle body structure

ABSTRACT

This provides a vehicle body structure including: a lower panel made of resin, which has a lower wall that forms a lower portion of a floor portion, an outer front wall that is placed to extend from a vehicle body front end of the lower wall to an upper direction of a vehicle body, and an outer back wall that is placed to extend from a vehicle body backside end of the lower wall to the upper direction of the vehicle body; and an upper panel made of resin, which has upper walls that form an upper portion of the floor portion opposite to the lower wall, an inner front wall that is placed to extend from the vehicle body front ends of the upper walls to the upper direction of the vehicle body and joined to the outer front wall and consequently forms a closed cross-section shape that extends in a vehicle width direction while including both of left and right ends at an upper portion of the outer front wall, and an inner back wall that is placed to extend from the vehicle body backside ends of the upper walls to the upper direction of the vehicle body and joined to the outer back wall and consequently forms a closed cross-section shape that extends in the vehicle width direction while including both of left and right ends at an upper portion of the outer back wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a national phase application based on the PCT InternationalPatent Application No. PCT/JP2012/055275 filed Mar. 1, 2012, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a vehicle body structure that containsa floor portion made of resin.

BACKGROUND ART

A vehicle body floor portion structure in which a locker, a floor panel,a dash panel, a cross member, a front cross member and a rear crossmember are made of carbon fiber reinforced plastic is conventionallyknown (for example, refer to Japanese Patent Application Publication No.2008-155700 (JP 2008-155700 A), Japanese Patent Application PublicationNo. 1-132474 (JP 1-132474 A) and Japanese Patent Application PublicationNo. 6-64559 (JP 6-64559 A). Also, a floor portion structure thatimproves a load transmission efficiency at a time of a collisionalthough the floor portion structure is not made of the resin isconventionally known (for example, refer to Japanese Patent ApplicationPublication No. 2003-285766 (JP 2003-285766 A), Japanese PatentApplication Publication No. 2008-49894 (JP 2008-49894 A) and JapaneseUtility Model Application Publication No. 3-84286 (JP 3-84286 U).

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, even in the vehicle body floor portion structure made of theresin, it is desired to efficiently transmit a load inputted from afront-back direction of a vehicle body at a time of a front surfacecollision or rear surface collision, and for the advancement of its loadtransmission efficiency, there is still room for improvement.

So, in view of the above circumstances, an object of the presentinvention is to obtain the vehicle body structure that can efficientlytransmit the load inputted from the front-back direction of the vehiclebody.

Means to Solve the Problem

In order to achieve the above-mentioned object, a vehicle body structureof a first aspect according to the present invention includes: a lowerpanel made of resin, which has a lower wall that configures a lowerportion of a floor portion, an outer front wall that is placed to extendfrom a vehicle body front end of the lower wall to an upper direction ofa vehicle body, and an outer back wall that is placed to extend from avehicle body backside end of the lower wall to the upper direction ofthe vehicle body; and an upper panel made of resin, which has an upperwall that configures an upper portion of the floor portion oppositely tothe lower wall and also configures a closed cross-section shapeextending in a front-back direction of the vehicle body, an inner frontwall that is placed to extend from the vehicle body front end of theupper wall to the upper direction of the vehicle body and joined to theouter front wall and consequently configures a closed cross-sectionshape that is connected to the closed cross-section shape extending inthe front-back direction of the vehicle body and extends in the vehiclewidth direction while including both of left and right ends at the upperportion of the outer front wall, and an inner back wall that is placedto extend from the vehicle body backside end portion of the upper wallto the upper direction of the vehicle body and joined to the outer backwall and consequently configures a closed cross-section shape that isconnected to the closed cross-section shape extending in the front-backdirection of the vehicle body and extends in the vehicle width directionwhile including both of the left and right ends at an upper portion ofthe outer back wall.

According to the first aspect of the present invention, since the outerfront wall of the lower panel and the inner front wall of the upperpanel are joined, thereby configuring the closed cross-section shapethat extends in the vehicle width direction while including both of theleft and right ends at its upper portion, and the outer back wall of thelower panel and the inner back wall of the upper panel are joined,thereby configuring the closed cross-section shape that extends in thevehicle width direction while including both of the left and right endsat its upper portion. Thus, a load, which is inputted from the vehiclebody front to the outer front wall, is transmitted to the outside in thevehicle width direction through its closed cross-section shape, and aload, which is inputted from the vehicle body backside to the outer backwall, is transmitted to the outside in the vehicle width directionthrough its closed cross-section shape.

Here, both of the left and right ends of the upper portion of thevehicle body front which are formed as the closed cross-section shapeare joined to a front pillar as a vehicle body framework member,respectively, and both of the left and right ends of the upper portionof the vehicle body backside which are formed as the closedcross-section shape are joined to a rear pillar as the vehicle bodyframework member, respectively. Thus, the loads, which are transmittedto the outsides in the vehicle width direction (both of the left andright ends of the respective upper portions) through the closedcross-section shapes, are transmitted to the front pillar or the rearpillar and absorbed thereby. In this way, according to the presentinvention, the load inputted from the front-back direction of thevehicle body can be efficiently transmitted to the front pillar or therear pillar.

Also, a vehicle body structure of a second aspect according to thepresent invention includes: a lower panel made of resin, which has alower wall that configures a lower portion of a floor portion, an outerfront wall that is placed to extend from a vehicle body front end of thelower wall to an upper direction of a vehicle body, and an outer backwall that is placed to extend from a vehicle body backside end of thelower wall to the upper direction of the vehicle body; an upper panelmade of resin, which has an upper wall that configures an upper portionof the floor portion oppositely to the lower wall and consequentlyconfigures a closed cross-section shape extending in a front-backdirection of the vehicle body; a front panel made of resin, which has aninner front wall, wherein since it is joined to the vehicle body frontend of the upper wall and the outer front wall, a closed cross-sectionshape that is connected to the closed cross-section shape extending inthe front-back direction of the vehicle body and extends in a vehiclewidth direction while including both of left and right ends isconfigured at an upper portion of the outer front wall; and a rear panelmade of resin, which has an inner back wall, wherein since it is joinedto the vehicle body backside end of the upper wall and the outer backwall, a closed cross-section shape that is connected to the closedcross-section shape extending in the front-back direction of the vehiclebody and extends in the vehicle width direction while including both ofleft and right ends is formed at an upper portion of the outer backwall.

According to the second aspect of the present invention, since the outerfront wall of the lower panel and the inner front wall of the frontpanel are joined, thereby configuring the closed cross-section shapethat extends in the vehicle width direction while including both of theleft and right ends at its upper portion, and the outer back wall of thelower panel and the inner back wall of the rear panel are joined,thereby configuring the closed cross-section shape that extends in thevehicle width direction while including both of the left and right endsat its upper portion. Thus, a load, which is inputted from the vehiclebody front to the outer front wall, is transmitted to the outside in thevehicle width direction through its closed cross-section shape, and aload, which is inputted from the vehicle body backside to the outer backwall, is transmitted to the outside in the vehicle width directionthrough its closed cross-section shape.

Here, both of the left and right ends of the upper portion of thevehicle body front which are formed as the closed cross-section shapeare joined to a front pillar as a vehicle body framework member,respectively, and both of the left and right ends of the upper portionof the vehicle body backside which are formed as the closedcross-section shape are joined to a rear pillar as the vehicle bodyframework member, respectively. Thus, the loads, which are transmittedto the outsides in the vehicle width direction (both of the left andright ends of the respective upper portions) through the closedcross-section shapes, are transmitted to the front pillar or the rearpillar and absorbed thereby. In this way, according to the presentinvention, the load inputted from the front-back direction of thevehicle body can be efficiently transmitted to the front pillar or therear pillar.

Also, a vehicle body structure of a third aspect according to thepresent invention is the vehicle body structure of the first or secondaspect, wherein the closed cross-section shape that is formed by atleast the outer front wall and the inner front wall is formed at aposition at which the closed cross-section shape overlaps with a doorbelt line in an upper-lower direction of the vehicle body, when they areviewed from the vehicle width direction.

According to the third aspect according to the present invention, theclosed cross-section shape, which is formed by at least the outer frontwall and the inner front wall when they are viewed from the vehiclewidth direction, overlaps with the door belt line in the upper-lowerdirection of the vehicle body. Thus, the load that is transmitted to theoutside of the vehicle width direction (both of the left and right endsof the upper portion) through its closed cross-section shape istransmitted even to the door belt line and absorbed thereby. In thisway, according to the present invention, the load that is inputted fromat least the front direction of the vehicle body can be efficientlytransmitted to the door belt line.

Also, a vehicle body structure of a fourth aspect according to thepresent invention is the vehicle body structure described in any one ofthe first to third aspects, wherein the closed cross-section shape thatis formed by at least the outer front wall and the inner front wall isformed continuously between both of the left and right ends.

According to the fourth aspect according to the present invention, theclosed cross-section shape, which is formed by at least the outer frontwall and the inner front wall, is formed continuously between both ofthe left and right ends. Thus, the load that is inputted from at leastthe front side of the vehicle body can be efficiently transmitted to theoutside of the vehicle width direction (both of the left and right endsof the upper portion), through its closed cross-section shape.

Effect of the Invention

As mentioned above, according to the present invention, it is possibleto efficiently transmit the load inputted from the front-back directionof the vehicle body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view showing a schematic configurationof an automobile that contains a resin body structure according to afirst embodiment.

FIG. 2 is an exploded perspective view showing an upper panel and alower panel, which form a floor portion of the resin body structureaccording to the first embodiment, when they are viewed from behind avehicle body.

FIG. 3 is an exploded perspective view showing the upper panel and thelower panel, which form the floor portion of the resin body structureaccording to the first embodiment, when they are viewed from before thevehicle body.

FIG. 4 is a perspective view showing the floor portion of the resin bodystructure according to the first embodiment when it is viewed frombehind the vehicle body.

FIG. 5 is a perspective view showing the floor portion of the resin bodystructure according to the first embodiment when it is viewed frombefore the vehicle body.

FIG. 6 is a perspective view, which shows a vehicle body front side ofthe floor portion of the resin body structure according to the firstembodiment, by enlarging the vehicle body front.

FIG. 7 is a cross-sectional view taken along an X-X line in FIG. 6,which shows a front suspension member, a front pillar and a door beltline while including a positional relation between them and the floorportion.

FIG. 8 is a cross-sectional view taken along a Y-Y line in FIG. 6.

FIG. 9 is a perspective view showing a variation example in the floorportion in which closed cross-section shapes are formed continuouslybetween both of left and right ends, when they are viewed from behindthe vehicle body.

FIG. 10 is a cross-sectional view taken on a Z-Z line in FIG. 9.

FIG. 11 is an exploded perspective view showing an upper panel, a lowerpanel, a front panel and a rear panel, which form a floor portion of aresin body structure according to a second embodiment, when they areviewed from behind the vehicle body.

FIG. 12 is a perspective view showing the floor portion of the resinbody structure according to the second embodiment when it is viewed frombehind the vehicle body.

MODES FOR CARRYING OUT THE INVENTION

The embodiment according to the present invention will be describedbelow in detail on the basis of the drawings. By the way, an arrow markFR that is arbitrarily shown in the drawing shows a front direction in avehicle body front-back direction, and an arrow mark UP shows an upperdirection in a vehicle body upper-lower direction, and an arrow mark OUTshows an outside in a vehicle width direction, respectively. Also, inthe following explanations, when the front-back, upper-lower andleft-right directions are used without any special mention, they aredefined to indicate the front-back direction in the vehicle bodyfront-back direction, the upper-lower direction in the vehicle bodyupper-lower direction, and the left-right direction in the vehicle bodyleft-right direction (the vehicle width direction), respectively.

As shown in FIG. 1, a resin body structure 10 as a vehicle bodystructure according to this embodiment is applied to an (electric)automobile V as a vehicle. This resin body structure 10 is formed sothat an under body 12, a front suspension module 14, a front energyabsorption member (hereafter, referred to as “a front EA member”) 16, arear suspension module 18 and a rear energy absorption member(hereafter, referred to as “a rear EA member”) 20 serve as mainportions.

(Configuration of Under Body According to First Embodiment)

At first, the first embodiment is explained. As shown in FIG. 2 and FIG.3, the under body 12 made of resin according to the first embodiment isformed by a lower panel 12L and an upper panel 12U. Since the lowerpanel 12L and the upper panel 12U are joined, a floor portion 22 (referto FIG. 1) whose shape is approximately rectangular in a plain view isformed.

Also, this under body 12 is formed to include: a dash lower portion 24as a front wall portion, which is placed upwardly from a front end ofthe floor portion 22; and a lower back portion 26 as a back wallportion, which is placed upwardly from a back end of the floor portion22. Each of the dash lower portion 24 and the lower back portion 26 hasa length equal to an approximately entire width of the floor portion 22,and in a front view, its vehicle width direction is formed as anapproximately rectangular shape in a longitudinal direction.

Also, as shown in FIG. 4 and FIG. 5, from both ends in the vehicle widthdirection of the dash lower portion 24, front walls 28 are backwardlyextended, and from both ends in the vehicle width direction of the lowerback portion 26, back walls 30 are forwardly extended. In the frontwalls 28 and the back walls 30, respective lower ends are connected toouter ends in the vehicle width direction of the floor portion 22 (alocker portion 36 that will be explained later) and separated from eachother in the front-back direction. As mentioned above, the under body 12is entirely formed as a bath tab shape (the bath tab shape in which apart of a side wall is cut).

Also, as shown in FIG. 1 to FIG. 5, the floor portion 22 has a lowerwall 32 that is flat along a substantially horizontal surface and upperwalls 40 and 44 that are opposite to this lower wall 32 in theupper-lower direction and flat along the substantially horizontalsurface. And, a pair of left and right locker portions 36 as sideframework structure portions in which the respective front-backdirections are defined as longitudinal directions, and a tunnel portion38 as a center framework structure portion are formed in this floorportion 22.

Each of the pair of left and right locker portions 36 is formed by thelower wall 32, the upper wall 40 as a locker wall which is opposite tothe lower wall 32 in the upper-lower direction, an outer wall 34 whichis upwardly placed from both sides in the vehicle width direction of thelower wall 32, and an inner wall 42 as a longitudinal wall opposite tothe outer wall 34 in the vehicle width direction (which faces thevehicle width direction), as a closed cross-section structure ofrectangular frame shape, in a front cross-sectional view viewed from thefront-back direction of the vehicle body.

The tunnel portion 38 is formed by the lower wall 32, the upper wall 44as a tunnel wall that is opposite to the lower wall 32 in theupper-lower direction, and center side walls 46 as a pair oflongitudinal walls opposite to each other (which faces the vehicle widthdirection), as a closed cross-section structure of rectangular frameshape, in a front cross-sectional view viewed from the front-backdirection of the vehicle body.

By the way, in this embodiment, the upper wall 40 on both sides in thevehicle width direction and the upper wall 44 at a center in the vehiclewidth direction are formed so that their opposite intervals from thelower wall 32 differ from each other. That is, the left and right lockerportions 36 are formed to be higher than the tunnel portion 38. Also,since the left and right locker portions 36 and the tunnel portion 38are formed in the floor portion 22, a lower groove portion 41 which isconcave in a front cross-sectional view viewed from the front-backdirection of the vehicle body is formed between the upper wall 40 andthe upper wall 44.

A rectangular opening 41A where a vehicle body backside endsubstantially arrives at a front wall 64 (that will be described later)and a vehicle body front end is tapered is formed in the lower grooveportion 41 on a front side of a center cross portion 60 that will bedescribed later. And, a rectangular opening 41B where the vehicle bodyfront end substantially arrives at a back wall 66 (that will bedescribed later) and the vehicle body backside end is tapered is formedin the lower groove portion 41 on a back side of its center crossportion 60.

Moreover, the lower groove portion 41 located on the vehicle body frontfrom the opening 41A (the vehicle body front portion except the opening41A in the lower groove portion 41 of the front side) serves as a jointportion 80 joined to the lower wall 32. Then, parts of the lower grooveportion 41 around the opening 41A except the joint portion 80 serve asupper flanges 12UF joined to the lower wall 32.

On the other hand, the lower groove portion 41 located on the vehiclebody backside from the opening 41B (the vehicle body backside portionexcept the opening 41B in the lower groove portion 41 of the back side)serves as a joint portion 82 joined to the lower wall 32. Then, parts ofthe lower groove portion 41 around the opening 41B except the jointportion 82 serve as the upper flanges 12UF joined to the lower wall 32.

Also, the dash lower portion 24 is formed as the three closedcross-section structures that are integrally continuous and locatedupwardly from the respective front ends of the left and right lockerportions 36 and the tunnel portion 38, as shown in FIG. 4. And, thelower back portion 26 is formed as the three closed cross-sectionstructures that are integrally continuous and located upwardly from therespective back ends of the left and right locker portions 36 and thetunnel portion 38, as shown in FIG. 5.

In detail, as shown in FIG. 2 and FIG. 4, the dash lower portion 24 isformed to have an outer front wall 48 and an inner front wall 50 whichare opposite to each other in the front-back direction, the lower wall32, an upper wall 52 opposite to the lower wall 32, and a lower wall 53formed on the inner front wall 50, which will be described later.

The inner front wall 50 has: inner walls 43 as longitudinal walls inwhich the inner walls 42 that form the left and right locker portions36, respectively, are extended to the vehicle body front and integrallyformed; center side walls 47 as longitudinal walls in which the centerside walls 46 configuring the tunnel portion 38 are extended to thevehicle body front and integrally formed; and front groove portions 51in which the lower groove portions 41 are extended to the vehicle bodyfront and integrally formed.

A rectangular (square) opening 51A is made in the front groove portion51. Also, rectangular (trapezoidal) openings 50A are made even in bothsides in the vehicle width direction of the inner front wall 50. And,since the two front groove portions 51 of the inner front wall 50 arejoined to the outer front wall 48, three closed cross-section shapes areput in order in the vehicle width direction, in the dash lower portion24.

In short, this dash lower portion 24 is designed so that with the lowerwall 32, the outer front wall 48, the inner front wall 50, the upperwall 52, the respective inner walls 43 and the respective center sidewalls 47, the three closed cross-section shapes are formed in thevehicle width direction. And, as shown in FIG. 6 to FIG. 8, at an upperend 24A of the dash lower portion 24, a closed cross-section shape whichextends in the vehicle width direction while including both of the leftand right ends (the front walls 28) is further formed.

That is, at the upper end 24A of the dash lower portion 24 on thevehicle body upside of the opening 51A (the front groove portion 51), asshown in FIG. 8, in a side cross-sectional view viewed from the vehiclewidth direction, the upper wall 52, the inner front wall 50, the lowerwall 53 that extends to the vehicle body front from the lower end of theinner front wall 50 and is opposite to the upper wall 52, and the outerfront wall 48 form a closed cross-section structure of rectangular frameshape.

By the way, the vehicle body front end of the lower wall 53 is linked tothe front groove portion 51. And, the upper end 24A of the dash lowerportion 24 on the vehicle body upside of the opening 50A is similarlydesigned so that with in a cross-sectional view, a closed cross-sectionshape of rectangular frame is formed by the upper wall 52, the innerfront wall 50, the lower wall 53 and the outer front wall 48.

Also, a part of the lower wall 53 is formed on a portion which islocated on the outside of the vehicle width direction of the lowergroove portion 41 and is extended to the vehicle body front of theinside in the vehicle width direction of the locker portion 36. Then, aclosed cross-section shape on the vehicle body upside of the opening 51Aand a closed cross-section shape of the vehicle body upside of theopening 50A are linked through a closed cross-section shape formed inits extension portion (both of the left and right sides of the dashlower portion 24). And, the closed cross-section shape at its upper end24A is formed up to a position (which includes the front walls 28) thatarrives at the front walls 28 which are both of the left and right endsof the floor portion 22.

Consequently, a closed cross-section shape that extends in the vehiclewidth direction (and that intersects a longitudinal direction of thelower groove portion 41) is formed to be formed at the upper end 24A ofthe dash lower portion 24 except the extension portion to the vehiclebody front of the tunnel portion 38.

By the way, the closed cross-section shape at this upper end 24A can bealso regarded to be formed over the vehicle width direction (andcontinuous between the front walls 28 as both of the left and rightends), through the closed cross-section shape formed in the extensionportion (a central portion of the dash lower portion 24) to the vehiclebody front of the tunnel portion 38.

Here, the front wall 28 (the closed cross-section shape) is joined to afront pillar (an A pillar) 84 as a vehicle body framework member, asshown in FIG. 7. And, the closed cross-section shape at the upper end24A is formed at a position at which the closed cross-section shapeoverlaps with (laps over) a door belt line 86 in the upper-lowerdirection of the vehicle body, in a side view viewed from the vehiclewidth direction.

Thus, a load transmission route is formed from the dash lower portion 24through the closed cross-section shape at its upper end 24A to the frontpillar 84 and the door belt line 86. By the way, the door belt line 86is formed as a closed cross-section shape, in a cross-sectional viewviewed from the front-back direction of the vehicle body.

Also, the closed cross-section shape formed at the upper end 24A of thedash lower portion 24 (and formed by the outer front wall 48, the innerfront wall 50, the upper wall 52 and the lower wall 53) may be formedover the vehicle width direction (and continuous from one end side inthe vehicle width direction to the other end side) without anyinterposition of the three closed cross-section shapes at the dash lowerportion 24, as shown in FIG. 9 and FIG. 10.

That is, each of an extension portion to the vehicle body front of thetunnel portion 38 and an extension portion to the vehicle body front,which is located on the outside of the vehicle width direction of thelower groove portion 41 and on the inside of the vehicle width directionof the locker portion 36 is cut away, and the opening 51A and theopening 50A are linked to each other in the vehicle width direction, andthe lower wall 53 opposite to the upper wall 52 may be formed over thevehicle width direction (and continuous between the front walls 28 asboth of the left and right portions).

According to this, the load inputted to the dash lower portion 24 can bemore efficiently transmitted through the closed cross-section shape atits upper end 24A to the left and right front pillars 84 and the doorbelt lines 86.

By the way, in this configuration, a flange 53F bent toward a vehiclebody downside is formed at a vehicle body front end of the lower wall53. and its flange 53F is joined to the outer front wall 48. Also, aflange 50F that is connected to the front groove portion 51 in thevehicle width direction is formed on the inner front walls 50 of thevehicle body front ends of the tunnel portion 38 and the locker portions36, and its flange 50F is joined to the outer front wall 48.

Also, the lower portion connected to the upper walls 40 and 44 of theinner front wall 50 is referred to as a slant wall 50S (refer to FIG.1). The slant wall 50S is slanted with respect to the front-back(horizontal) direction so that its back end side is located lower thanits front end side. Then, its front upper end is connected to a lowerend of an upper-lower wall 50V (refer to FIG. 1) that is substantiallylocated along the upper-lower direction of the inner front wall 50. And,a back lower end of the slant wall 50S is connected to a front end ofthe upper wall 40 or 44.

On the other hand, as shown in FIG. 3 and FIG. 5, the lower back portion26 is formed to have an outer back wall 54 and an inner back wall 56that are opposite to each other in its front-back direction, the lowerwall 32, an upper wall 58 opposite to the lower wall 32, and a lowerwall 59 which is formed on the inner back wall 56 and will be describedlater.

The inner back wall 56 has: inner walls 45 as longitudinal walls inwhich inner walls 42 that form the left and right locker portions 36,respectively, are extended to the vehicle body backside and integrallyformed; center side walls 49 as longitudinal walls in which the centerside walls 46 that form the tunnel portion 38 are extended to thevehicle body backside and integrally formed; and back groove portions 57in which the lower groove portions 41 are extended to the vehicle bodybackside and integrally formed.

A rectangular (oblong) opening 57A is made in the back groove portion 57(refer to FIG. 2). And, since the two back groove portions 57 of theinner back wall 56 are joined to the outer back wall 54 and a protrusionwall 54A that is integrated with the outer back wall 54 so as toprotrude to the vehicle body backside, the three closed cross-sectionshapes are put in order in the vehicle width direction in the lower backportion 26.

In short, in this lower back portion 26, the three closed cross-sectionshapes are formed by the lower wall 32, the outer back wall 54, theinner back wall 56, the upper wall 58, the respective inner walls 45 andthe respective center side walls 49, in the vehicle width direction.And, similarly to the dash lower portion 24, a closed cross-sectionshape that extends in the vehicle width direction while including bothof left and right ends (the back walls 30) is further formed at an upperend 26A of the lower back portion 26.

That is, in the upper end 26A of the lower back portion 26 on thevehicle body upside of the opening 57A (the back groove portion 57), ina side cross-sectional view viewed from the vehicle width direction, theupper wall 58, the inner back wall 56, a lower wall 59 that extends tothe vehicle body backside from the lower end of the inner back wall 56and is opposite to the upper wall 58, and the outer back wall 54 form aclosed cross-section shape of rectangular frame shape. And, the vehiclebody backside end of the lower wall 59 is linked to the back grooveportion 57.

Consequently, a closed cross-section shape that extends in the vehiclewidth direction (and intersects the longitudinal direction of the lowergroove portion 41) is formed at the upper end 26A of the lower backportion 26, except the extension portion to the vehicle body backside ofthe tunnel portion 38 and the extension portion to the vehicle bodybackside of the locker portion 36.

By the way, the closed cross-section shape at this upper end 26A canalso be regarded to be formed over the vehicle width direction (whichincludes the back walls 30 as both of the left and right ends and iscontinuous between its back wall 30) through the closed cross-sectionshape formed in the extension portion (the center of the lower backportion 26) to the vehicle body backside of the tunnel portion 38 andthe closed cross-section shape formed in the extension portion (both ofthe left and right sides of the lower back portion 26) to the vehiclebody backside of the locker portion 36.

Here, the back wall 30 (of the closed cross-section shape) is joined toa rear pillar (a C pillar: its illustration is omitted) as the vehiclebody framework member. Thus, a load transmission route is formed fromthe lower back portion 26 through the closed cross-section shape at itsupper end 26A to the rear pillar.

By the way, similarly to the dash lower portion 24, in such a way thatthe closed cross-section shape which is formed at the upper end 26A ofthe lower back portion 26 (and formed by the outer back wall 54, theinner back wall 56, the upper wall 58 and the lower wall 59) is arrangedat a position where the closed cross-section shape overlaps with (lapsover) the door belt line 86 in the vehicle body upper-lower direction,in a side cross-sectional view viewed from the vehicle width direction,a height of its lower back portion 26 may be made high.

Also, similarly to the dash lower portion 24 (as shown in FIG. 9 andFIG. 10), the closed cross-section shape formed at the upper end 26A ofthe lower back portion 26 may be formed over the vehicle width direction(continuous from one end side of the vehicle width direction to theother end side).

That is, it may be formed so that the extension portion to the vehiclebody backside of the tunnel portion 38 is cut away and the opening 57Ais linked in the vehicle width direction, and even the extension portionto the vehicle body backside of the locker portion 36 is cut away andthe opening 57A is extended to the outside in the vehicle widthdirection, and the lower wall 59 opposite to the upper wall 58 is formedover the vehicle width direction (continuous between the back walls 30as both of the left and right ends).

According to this, similarly to the dash lower portion 24, the loadinputted to the lower back portion 26 can be more efficientlytransmitted to the left and right rear pillars (and the door belt line86) through the closed cross-section shape at its upper end 26A.

Also, a lower portion connected to the upper walls 40 and 44 of theinner back wall 56 is referred to as a slant wall 56S (refer to FIG. 1).The slant wall 56S is slanted with respect to the front-back(horizontal) direction so that its front end side is located lower thanits back end side, and its back upper end is connected to the lower endof an upper-lower wall 56V (refer to FIG. 1) that is substantially alongthe upper-lower direction of the inner back wall 56. And, the frontlower end of the slant wall 56S is connected to the back end of theupper wall 40 or upper wall 44.

Also, as shown in FIG. 1 to FIG. 5, the floor portion 22 has the centercross portion 60 (and extends in the vehicle width direction) throughwhich the left and right locker portions 36 and the tunnel portion 38are bridged at the substantial center in the vehicle body front-backdirection. The center cross portion 60 is formed as the closedcross-section structure of rectangular frame shape, in a sidecross-sectional view, by the lower wall 32, an upper wall 62 as a crosswall which is opposite to the lower wall 32 in the upper-lowerdirection, and a front wall 64 and a back wall 66 which are opposite toeach other in the front-back direction.

The under body 12 as explained above is made of resin material. As theresin material of which the under body 12 is made, for example,fiber-reinforced resin that contains reinforced fiber such as carbonfiber, glass fiber, aramid fiber and the like is listed.

And, this under body 12 (the floor portion 22) is formed so that asshown in FIG. 2 to FIG. 5, the lower panel 12L and the upper panel 12Uare overlapped with each other in the upper-lower direction and joinedwith adhesive.

In detail, the lower panel 12L is formed to include the lower wall 32,the outer wall 34, the outer front wall 48 of the dash lower portion 24,the outer back wall 54 of the lower back portion 26, outer walls 28A ofthe front walls 28, outer walls 30A of the back walls 30, and lowerflanges 12LF that are thrown outwardly from a circumferential edge in aplain view.

The upper panel 12U is formed to include: the upper wall 40 and theinner wall 42 of the locker portion 36; the upper wall 44 and the centerside wall 46 of the tunnel portion 38; the inner front wall 50, theupper wall 52, the lower wall 53, the inner walls 43 and the center sidewalls 47 of the dash lower portion 24; the inner back wall 56, the upperwall 58, the lower wall 59, the inner wall 45 and the center side wall49 of the lower back portion 26, the upper wall 62, the front wall 64and the back wall 66 of the center cross portion 60, inner walls 28B ofthe front walls 28, inner walls 30B of the back walls 30, and the upperflange 12UF that is thrown outwardly from a circumferential edge in aplain view.

And moreover, this upper panel 12U is formed to include the lower grooveportions 41 (the joint portions 80 and 82) formed between the tunnelportion 38 and the locker portions 36, the front groove portion 51formed on the inner front wall 50, and the back groove portion 57 formedon the inner back wall 56. By the way, as mentioned above, the upperflanges 12UF may be also formed in parts of the lower groove portions 41around the openings 41A and 41B except the joint portions 80 and 82.

Thus, in the under body 12, the lower panel 12L and the upper panel 12Uare adhered to each other because the lower flange 12LF and the upperflange 12UF are joined to each other, the lower wall 32 and the upperflange 12UF are joined to each other, the lower wall 32 and the jointportions 80 and 82 are joined to each other, the outer front wall 48 andthe front groove portion 51 are joined to each other, and the outer backwall 54 and the back groove portion 57 are joined to each other,respectively, and the above respective closed cross-section structuresare formed. By the way, in the front wall 28, the closed cross-sectionstructure is formed by the outer wall 28A and the inner wall 28B, and inthe back wall 30, the closed cross-section structure is formed by theouter wall 30A and the inner wall 30B.

(Configuration of Suspension Module)

As shown in FIG. 1, the front suspension module 14 is formed to at leastinclude a front suspension member 70 and a pair of left and right frontsuspensions that are not shown. In the front suspension member 70, thevehicle width direction is defined as the longitudinal direction, and itis defined as a closed cross-section structure in a side cross-sectionalview in FIG. 1.

Also, in the front suspension member 70, the left and right frontsuspensions are assembled as a whole. Then, the front suspension member70 steerably supports front wheels Wf through the respective frontsuspensions. That is, the respective front suspensions are supported bythe front suspension member 70 so as to independently carry out afunction without any dependence on the other portions that form thevehicle body of the automobile V.

On the other hand, the rear suspension module 18 is formed to at leastinclude a rear suspension member 72 and a pair of left and right rearsuspensions that are not shown. In the rear suspension member 72, theleft and right rear suspensions are assembled as a whole. Then, the rearsuspension member 72 rotatably supports rear wheels Wr through therespective rear suspensions. That is, the respective rear suspensionsare supported by the rear suspension member 72 so as to independentlycarry out a function without any dependence on the other portions thatform the vehicle body of the automobile V.

Moreover, a wheel-in motor that is not shown is built in the rear wheelWr. And, a battery, which is not shown, for driving the wheel-in motorand a PCU (Power Control Unit) serving as a control device are assembledin the rear suspension module 18. Thus, the rear suspension module 18can be also regarded as a driving unit of the automobile V.

And, the front suspension member 70 is fixed to the car body front ofthe dash lower portion 24 because its back wall 78 is fastened to anouter front wall 48, and its flange 74 is fastened to the joint portion80 (the lower wall 32). Also, the rear suspension member 72 is fixed tothe vehicle body backside of the lower back portion 26 because itsattachment plate 68 is fastened to a protrusion wall 54A of the outerback wall 54, and its flange 76 is fastened to the joint portion 82 (thelower wall 32).

(Configuration of EA Member)

As shown in FIG. 1, the front EA member 16 is formed as a box shape(substantially rectangular box shape) that has a length along thevehicle width direction which is approximately equal to a length (aninterval between the left and right front suspensions) of the vehiclewidth direction of the front suspension member 70. And, this front EAmember 16 is fastened and fixed to the front suspension member 70 in aflange 16F that is thrown from its back end.

On the other hand, the rear EA member 20 is formed as a box shape(substantially rectangular box shape) that has a length along thevehicle width direction which is approximately equal to a length (aninterval between the left and right rear suspensions) of the vehiclewidth direction of the rear suspension member 72. And, this rear EAmember 20 is fastened and fixed to the rear suspension member 72 in aflange 20F that is thrown from both ends of its vehicle width direction.

In the front EA member 16 and the rear EA member 20 as mentioned above,the respective portions are integrally made of resin material. As theresin material of which the front EA member 16 or the rear EA member 20is made, for example, the fiber-reinforced resin that contains thereinforced fiber, such as the carbon fiber, the glass fiber, the aramidfiber and the like, is listed. Also, the front EA member 16 or the rearEA member 20 may be made of metal material such as aluminum and itsalloy and the like.

(Action)

With regard to the resin body structure 10 having the foregoingconfiguration, its action will be described below.

The (electric) automobile V to which the resin body structure 10according to this embodiment is applied is run by the driving force ofthe wheel-in motor because an electric power is supplied from the PCUbuilt in the rear suspension member 72 to the wheel-in motor of the rearwheel Wr. And, in this automobile V, the front wheel Wf supportedthrough the front suspension is steered in response to the steering of asteering wheel that is not shown.

In this automobile V, when a front collision is generated, a collisionload is inputted to the front EA member 16. This collision load causesthe front EA member 16 to be compressed and deformed. Consequently, thefront EA member 16, while absorbing an impact energy (a dynamic load),transmits a load (a support reaction force) to the front suspensionmember 70.

At this time, the collision load inputted to the front EA member 16 isreceived by the wide surface (the wall long in the vehicle widthdirection) of the front suspension member 70, and the front EA member 16is stably compressed and deformed. Thus, the absorption of the collisionload by the front EA member 16 is efficiently executed.

And, the collision load, which is transmitted to the front suspensionmember 70 because the collision load is not completely absorbed by thefront EA member 16, is transmitted through the dash lower portion 24 tothe floor portion 22, and then absorbed by the floor portion 22.

In detail, the load, which is inputted from the front EA member 16through the back wall 78 of the front suspension member 70 to the dashlower portion 24, is received by the three closed cross-sectionstructures fainted in the dash lower portion 24, namely, the respectiveinner walls 43 of the inner front wall 50 and the respective center sidewalls 47 which form the respective closed cross-section structures,respectively.

For this reason, it is possible to suppress a bent deformation to thevehicle body backside of the outer front wall 48. Also, the load can betransmitted from the respective inner walls 43 of the inner front wall50 and the respective center side walls 47 to ridge lines R1 (refer toFIG. 4) on the respective inner walls 42 on the front of the lockerportion 36 and ridge lines R2 (refer to FIG. 4) on the respective centerside walls 46 on the front of the tunnel portion 38.

In short, the three closed cross-section structures (the closedcross-section shapes) formed in the dash lower portion 24 are formedwhile being connected to the locker portions 36 and the tunnel portion38 of the floor portion 22, respectively. Thus, the load inputted to thedash lower portion 24 is efficiently transmitted from the dash lowerportion 24 to the locker portions 36 and the tunnel portion 38 of thefloor portion 22 and absorbed thereby.

Also, the closed cross-section shape that extends in the vehicle widthdirection while including both of the left and right ends (the frontwalls 28) is formed at the upper end 24A of the dash lower portion 24.And, its closed cross-section shape is connected to the front pillars 84and the door belt line 86 so that the load can be transmitted to thefront pillars 84 and the door belt line 86 (the front walls 28 arejoined to the front pillars 84, and the upper end 24A overlaps with thedoor belt line 86 in the upper-lower direction).

Thus, the load that is inputted (transmitted) to the dash lower portion24 is efficiently transmitted through the closed cross-section shape,which is formed in its upper end 24A, even to the front pillars 84 andthe door belt line 86 and also absorbed by the front pillars 84 and thedoor belt line 86. Hence, the deformation in the floor portion 22 can besuppressed more efficiently.

By the way, as shown in FIG. 9 and FIG. 10, in a case that the closedcross-section shape formed in the upper end 24A of the dash lowerportion 24 is formed continuously between both of the left and rightends (the front walls 28), the load can be furthermore efficientlytransmitted to the front pillars 84 and the door belt line 86.

Also, in this automobile V, when a rear surface collision is generated,a collision load is inputted to the rear EA member 20. This collisionload causes the rear EA member 20 to be compressed and deformed.Consequently, the rear EA member 20, while absorbing an impact energy (adynamic load), transmits a load (a support reaction force) to the rearsuspension member 72.

At this time, the collision load inputted to the rear EA member 20 isreceived by the wide surface (the wall long in the vehicle widthdirection) of the rear suspension member 72, and the rear EA member 20is stably compressed and deformed. Thus, the absorption of the collisionload by the rear EA member 20 is efficiently executed.

And, the collision load, which is transmitted to the rear suspensionmember 72 because the collision load is not completely absorbed by therear EA member 20, is transmitted through the lower back portion 26 tothe floor portion 22, and then absorbed by the floor portion 22.

In detail, the load, which is inputted from the rear EA member 20through the attachment plate 68 of the rear suspension member 72 to thelower back portion 26, is received by the three closed cross-sectionstructures formed in the lower back portion 26, namely, the respectiveinner walls 45 of the inner back wall 56 and the respective center sidewalls 49 which form the respective closed cross-section structures,respectively.

For this reason, it is possible to suppress a bent deformation to thevehicle body front of the outer back wall 54. Also, the load can betransmitted from the respective inner walls 45 of the inner back wall 56and the respective center side walls 49 to ridge lines R3 (refer to FIG.5) on the respective inner walls 42 on the backside of the lockerportion 36 and ridge lines R4 (refer to FIG. 5) on the respective centerside walls 46 on the backside of the tunnel portion 38.

In short, the three closed cross-section structures (the closedcross-section shapes) formed in the lower back portion 26 are formedwhile being connected to the locker portions 36 and the tunnel portion38 of the floor portion 22, respectively. Thus, the load inputted to thelower back portion 26 is efficiently transmitted from the lower backportion 26 to the locker portions 36 and the tunnel portion 38 of thefloor portion 22 and absorbed thereby.

Also, the closed cross-section shape that extends in the vehicle widthdirection while including both of the left and right ends (the backwalls 30) is formed at the upper end 26A of the lower back portion 26.And, its closed cross-section shape is connected to the rear pillars sothat the load can be transmitted to the rear pillars (the back walls 30are joined to the rear pillar).

Thus, the load that is inputted (transmitted) to the lower back portion26 is efficiently transmitted through the closed cross-section shape,which is formed in its upper end 26A, even to the rear pillars and alsoabsorbed by its rear pillars. Hence, the deformation in the lower backportion 26 can be suppressed more efficiently.

By the way, as mentioned above, in a case that the closed cross-sectionshape formed in the upper end 26A of the lower back portion 26 overlapswith the door belt line 86 in the upper-lower direction, the load can beefficiently transmitted to even its door belt line 86.

Also, as mentioned above, in a case that the closed cross-section shapeformed in the upper end 26A of the lower back portion 26 is formedcontinuously between both of the left and right ends (the back walls30), the load can be furthermore efficiently transmitted to the rearpillars (and the door belt line 86).

Also, in this automobile V, even when a side collision is formed, acollision load inputted by The side collision is received (absorbed) inthe center cross portion 60 formed in the closed cross-section structurein the floor portion 22. In short, the load inputted from the vehiclebody side (the outside in the vehicle width direction) is efficientlytransmitted to the center cross portion 60 and absorbed thereby. Thus,it is possible to suppress the deformation in the floor portion 22.

(Configuration of Under Body According to Second Embodiment)

Next, the second embodiment will be described below. By the way, thesame symbol is assigned to a portion similar to the first embodiment,and its detailed explanation (that includes an action) is omitted.

As shown in FIG. 11, an under body 12 made of resin according to thesecond embodiment is formed by a lower panel 12L, an upper panel 12U, afront panel 12F and a rear panel 12R. That is, the front panel 12F andthe rear panel 12R are joined to the lower panel 12L and the upper panel12U that are joined to each other. Consequently, the floor portion 22that has a substantially rectangular shape in a plain view is formed.

The lower panel 12L according to the second embodiment is equal to thatof the first embodiment. And, the upper panel 12U according to thesecond embodiment has a shape which differs from that of the firstembodiment. In detail, this upper panel 12U is formed to have the upperwalls 40 and 44, the inner walls 42, the center side walls 46, the frontwalls 64, the back walls 66 and the upper flanges 12UF, except the wallportion which forms the dash lower portion 24 and the lower back portion26. Then, those vehicle body front end and vehicle body back end areextended so as to arrive at the outer front wall 48 and the outer backwall 54, respectively.

On the other hand, the front panel 12F has the inner wall 28B (the frontwall 28) and the wall portion that forms the dash lower portion 24,namely, the inner front wall 50, the upper wall 52, the lower wall 53,the inner walls 43, the center side walls 47 and the front grooveportions 51, and the opening 51A is made in each of the front grooveportions 51. Then, the openings 50A are made in both of the left andright sides of the inner front wall 50. By the way, the vehicle bodybackside of each of the front groove portions 51, namely, a portionbetween the center side wall 47 and the inner wall 43 is cut out to arectangular shape, and flanges 12FF are formed in the circumferentialedge of its cutout 55 and the circumferential edge of the lower end ofthe inner front wall 50.

Also, the rear panel 12R has the inner walls 30B (the back walls 30),and the wall portion that forms the lower back portion 26, namely, theinner back wall 56, the upper wall 58, the lower wall 59 (refer to FIG.3 and FIG. 5), the inner walls 45, the center side walls 49 and the backgroove portions 57. Then, the opening 57A is made in each of the backgroove portions 57. By the way, the vehicle body front of each of theback groove portions 57, namely, a portion between the center side wall49 and the inner wall 45 is cut away. Then, flanges (whose illustrationsare omitted) are formed in the circumferential edge of its cutout 55 andthe circumferential edge of the lower end of the inner back wall 56.

Thus, as shown in FIG. 11 and FIG. 12, after the lower panel 12L and theupper panel 12U are joined to each other, the flanges 12FF of the frontpanel 12F are joined to the upper flanges 12UF and the upper walls 40and 44 of the upper panel 12U from above, and the front groove portions51 of the front panel 12F are joined to the outer front wall 48.Consequently, its front panel 12F is fixed to the lower panel 12L andthe upper panel 12U.

Similarly, after the lower panel 12L and the upper panel 12U are joinedto each other, the flanges (whose illustrations are omitted) of the rearpanel 12R are joined to the upper flanges 12UF and the upper walls 40and 44 of the upper panel 12U from above, and the back groove portions57 of the rear panel 12R are joined to the outer back wall 54.Consequently, its rear panel 12R is fixed to the lower panel 12L and theupper panel 12U.

The floor portion 22 (the under body 12) according to the secondembodiment as configured above becomes equal to that of the firstembodiment. That is, even in the floor portion 22 (the under body 12)according to the second embodiment, similarly to the first embodiment,the closed cross-section shapes that include both of the left and rightends (the front walls 28 and the back walls 30) and extend in thevehicle width direction are formed at the upper end 24A of the dashlower portion 24 and the upper end 26A of the lower back portion 26 (itincludes a case that the closed cross-section shape is formedcontinuously between both of the left and right ends).

Also, in the floor portion 22 according to this second embodiment, theupper panel 12U according to the first embodiment is shaped to bedivided into three components. Thus, a mold used in this secondembodiment has a merit that its structure can be made simple, ascompared with a mold for molding the upper panel 12U according to thefirst embodiment. In short, the dash lower portion 24 and the lower backportion 26 can be molded independently of each other. Thus, even if theshapes of the dash lower portion 24 and the lower back portion 26 arecomplicated, it is possible to easily correspond to the complicatedshapes.

As explained above, according to the resin body structure 10 of thisembodiment, the load inputted to the dash lower portion 24 at the timeof the front collision can be efficiently transmitted to the frontpillars 84 and the door belt line 86 (the upper body) which serve as thevehicle body framework members. And, the load inputted to the lower backportion 26 at the time of the back collision can be efficientlytransmitted to the rear pillar (and the door belt line 86) (the upperbody) which serves as the vehicle body framework member.

In short, according to the resin body structure 10 of this embodiment,the collision load generated at the time of the front collision or backcollision can be efficiently transmitted not only to the floor portion22 but also to the front pillar 84 and the rear pillar and further tothe door belt line 86. Thus, the load absorbed by (burdened on) thefloor portion 22 can be reduced, thereby enabling the deformation in avehicle chamber (the floor portion 22) to be more effectivelysuppressed.

Also, even if the under body 12 is made of resin, the dash lower portion24 and the lower back portion 26 each of which has the three closedcross-section structures can be made function as energy absorptionmaterials at the time of the collision. Thus, as compared with aconfiguration to which a different energy absorption material is added,the cost and weight of the automobile V can be reduced.

In particular, the openings 41A, 41B, 50A, 51A and 57A are made in theupper panel 12U according to the first embodiment, respectively, and theopenings 41A, 41B, 50A and 51A are made in the front panel 12F accordingto the second embodiment, respectively. Also, the opening 57A is made inthe rear panel 12R. Thus, the weight can be further reduced.

As mentioned above, the vehicle body structure (the resin body structure10) according to this embodiment has been explained on the basis of thedrawings. However, the vehicle body structure (the resin body structure10) according to this embodiment is not limited to the shown structures.Its design can be properly changed in a range without departing from thespirit and scope of the present invention. For example, the upper panel12U and the lower panel 12L, and further, the front panel 12F and therear panel 12R may be formed so as to be joined by fusing or welding.

Also, the closed cross-section shapes, which are formed in the dashlower portion 24 and the lower back portion 26 so as to extend in thevehicle width direction, respectively, are not limited to theconfigurations formed in the respective upper ends 24A and 26A. That is,those closed cross-section shapes may be formed to be formed above theupper portion of the dash lower portion 24 and the upper portion of thelower back portion 26, which are slightly lowered from the upper walls52 and 58, respectively.

Description of the Reference Numerals and Symbols

10/ RESIN BODY STRUCTURE (VEHICLE BODY STRUCTURE)

12/ UNDER BODY

12U/ UPPER BODY

12L/ LOWER PANEL

12F/ FRONT PANEL

12R/ REAR PANEL

22/ FLOOR PORTION

32/ LOWER WALL

40/ UPPER WALL

44/ UPPER WALL

48/ OUTER FRONT WALL

50/ INNER FRONT WALL

54/ OUTER BACK WALL

56/ INNER BACK WALL

86/ DOOR BELT LINE

The invention claimed is:
 1. A vehicle body structure comprising: alower panel made of resin that includes a lower wall that forms a lowerportion of a floor portion, an outer front wall that is placed to extendfrom a vehicle body front end of the lower wall to an upper direction ofa vehicle body, and an outer back wall that is placed to extend from avehicle body backside end of the lower wall to the upper direction ofthe vehicle body; and an upper panel made of resin that includes anupper wall that forms an upper portion of the floor portion opposite tothe lower wall and also forms a closed cross-section shape extending ina front-back direction of the vehicle body, an inner front wall that isplaced to extend from the vehicle body front end of the upper wall tothe upper direction of the vehicle body and joined to the outer frontwall and that forms a closed cross-section shape that is connected tothe closed cross-section shape extending in the front-back direction ofthe vehicle body and extends in a vehicle width direction whileincluding both of left and right ends at the upper portion of the outerfront wall, and an inner back wall that is placed to extend from avehicle body backside end portion of the upper wall to the upperdirection of the vehicle body and joined to the outer back wall and thatforms a closed cross-section shape that is connected to the closedcross-section shape extending in the front-back direction of the vehiclebody and extends in the vehicle width direction while including both ofleft and right ends at an upper portion of the outer back wall.
 2. Avehicle body structure comprising: a lower panel made of resin thatincludes a lower wall that forms a lower portion of a floor portion, anouter front wall that is placed to extend from a vehicle body front endof the lower wall to an upper direction of a vehicle body, and an outerback wall that is placed to extend from a vehicle body backside end ofthe lower wall to the upper direction of the vehicle body; an upperpanel made of resin that includes an upper wall that forms an upperportion of the floor portion opposite to the lower wall and that forms aclosed cross-section shape extending in a front-back direction of thevehicle body; a front panel made of resin that includes an inner frontwall that is joined to the vehicle body front end of the upper wall andthe outer front wall and that forms a closed cross-section shape that isconnected to the closed cross-section shape extending in the front-backdirection of the vehicle body and extends in a vehicle width directionwhile including both of left and right ends at an upper portion of theouter front wall; and a rear panel made of resin that includes an innerback wall that is joined to the vehicle body backside end of the upperwall and the outer back wall and that forms a closed cross-section shapethat is connected to the closed cross-section shape extending in thefront-back direction of the vehicle body and extends in the vehiclewidth direction while including both of left and right ends at an upperportion of the outer back wall.
 3. The vehicle body structure accordingto the claim 1, wherein the closed cross-section shape that isconfigured by at least the outer front wall and the inner front wall isformed at a position at which the closed cross-section shape overlapswith a door belt line in an upper-lower direction of the vehicle body,when they are viewed from the vehicle width direction.
 4. The vehiclebody structure according to claim 1, wherein the closed cross-sectionshape that is configured by at least the outer front wall and the innerfront wall is formed continuously between both of the left and rightends.
 5. The vehicle body structure according to the claim 2, whereinthe closed cross-section shape that is configured by at least the outerfront wall and the inner front wall is formed at a position at which theclosed cross-section shape overlaps with a door belt line in anupper-lower direction of the vehicle body, when they are viewed from thevehicle width direction.
 6. The vehicle body structure according toclaim 2, wherein the closed cross-section shape that is configured by atleast the outer front wall and the inner front wall is formedcontinuously between both of the left and right ends.